You can now directly link to launching an image in Amazon EC2 console, combine that with this tool to open your browser to the right page.
$ ami=$(ubuntu-ami us-west-1 oneiric daily i386)
$ gnome-open https://console.aws.amazon.com/ec2/home?region=us-west-1#launchAmi=${ami}

Download and extract the latest tarball for lucid

Here, 'pubname' is the recommended "publish name" of this AMI, which happens to correspond to the basename of the name on EC2, and "url" is a fully qualified url to http://cloud-images.ubuntu.com .
$ wget $(ubuntu-ami -f "%{url} -O %{pubname}.tar.gz")
$ uec-publish-tarball *.tar.gz my-ubuntu-images

I don't think I'll get this into 11.10, but I'd like to have something with this function into 12.04, and support launching AMIs directly through it for ease of use. I'd love to hear input on what you'd like a "ubuntu-run-instance" command to look like and do.